I'm not sure how to even ask for a specific solution. If I could send to multiple usernames that would be great, but even if I could generate an email list from a list of specific usernames, that would be fine as well since I could then copy and paste those emails into t-bird which automatically formats them with commas.
There may already be some kind of solution in the core for this and I just haven't found it yet. I hope to get some interest on this as I do need a solution for this. Anyone else interested in participating in this please sound off, but even if I am the only one I'm willing to foot the cost on it if someone is willing to write an add on.